Induction heating machine with controls



June 1953 w. L. CORTEGGIANO ETAL 2,

INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 8 Sheets-Sheet 1 WITNESSES: INVENTORS A William 1.. Corteggiono,Milton P. Vore 6 and dohg M. Edwards.

I 1 M M M'TORNEY June 30, 1953 w. CORTEGGIANO ETAL 2,644,075

INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 8 Sheets-Sheet 2 WITNESSES: 'NVENTORS WIHmm L. Corteggmno Milton P. Vore :1 and John M. Edwards.

ATTORNEY June 30, 1953 w. L. CORTEGGIANO ET AL 2,544,075

INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 s Sheets-Sheet s Fig.4.

Full Operation Scanner Only Generator .n Q a WITNESSES: g ,2 i 3 5 INVENTORS I 1 N WIHICIIIT L. Corfeggicmo Milton P. Vore M and John M.Edwords.

I v Bil/7mm ATTO RN EY m 1953 w. CORTEGGIANO ETAL 2,644,075

INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 8 Sheets-Sheet 4 Fig.5.

.L E45 no Z I50 a 8 2 8 I00 7 Q l i I06 '04 L N0? 95 I WITNESSES: H INVENTORS wllhum L. Correggiuno, Milton P. Vore.

and J o hn M. Edwards.

ATTORNEY June 30, 1953 W. L. CORTEGGIANO ET'AL INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 Fig.6.

8 Sheets-Sheet 5 WITNESSES:

INVENTORS William Llcorteggiuno ,Milion R Vore 0nd J hg M. Edwards.

3 A4 a a/" ATTORNEY W William L. Corteggiono ,Milion P. Vore and dohg M. Edwards.

June 30, 1953 w. 1.. CORTEGGIANO ETAL 2,644,075

INDUCTION HEATING MACHINE WITH CONTROLS v Filed July 15, 1949 8 Sheets-Sheet 6 Fig.7.

, Fig.8. if ,L '9 m J [L 1% Fig9. I nos [I02 J} F M l Fig.l0.

leo J IGIJ H62 Figlll.

lssk I64 165 Has WITNESSES: INVENTORS ATTORNEY June 30, 1953 w. CORTEGGIANO ETI'AL 2,6

INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15. 1949 a Sheets-Sheet 7 Fig. l4.

WITNESSES: INVENTORS WilliumL. Corteggiono, Milton F? Vore W M ond JgYl'm Edwards.

ATTORNEY June 30, 1953 W. L. CORTEGGIANO El'AL INDUCTION HEATING MACHINE WITH CONTROLS Filed July 15, 1949 8 Sheets-Sheet 8 I INV ENTORS wllhum L. Cor'regglono, MIHOI'I I? Vore and .goYhn M. Edwards.

fl- W ATTO RN EY Patented June 30, 1953 UNITED STATES PATENT OFFICE more, Md., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationJuly 15, 1949,1Serial N'o. 1 04,944

8 Claims.

Broadly, this invention is-directed to :an induction heating machine adapted to heat-treat short round bars, rods and similar workpieces successively passed end to end through the machine; but the machine and parts thereof are useful for other purposes. More specifically, this invention is directed to providing an induction heating machine adapted to case harden batches of shifter rails for automobiles, the shifter-rails of a'batch being the same within'manufacturing tolerances, but different from the rails of a different batch.

A very important object'of our invention is to provide an induction heating machine having means .for heat-treating production workpieces as they move horizontally through the machine rather than down a slope or vertically as in the prior art.

An overall purpose of the invention is to provide an induction heating machine which 'is rugged, which is economical in operation, which minimizes handling of the workpieces, which is substantially foolproof in operation so that it can be operated by unskilled labor, and which is sufficiently flexible to heat-treat batches of workpieces which diifer in size or :shape or other properties.

.An importantobject of our. invention is to provide an induction heating machine adapted to heat shifter rails and similar workpieces on a mass production basis by the use of high fresort of shifter rail or other workpiece to a production run for another sort :of shifter rail :or other workpiece.

A further object of our invention is to provide an induction heatingmachine adapted to be differently set up to heat-treat different sorts of workpieces, but in'such amanner that for each particular setup it will receive only a single sort of workpieces.

An important object of our "invention is to provide a machine o'f the type described which More specifically,

induction heating coil should the machine lack pieces of work or otherwise tend to operate improperly.

Still another objectof our invention is to provide an induction heating machine of a type described in which dummy pieces or substitute work is supplied to the machine after all of the production workpieces to be heat-treated have been processed so thatit is impossible to get a partial- 1y processed workpiece in the batch. In this connection the dummy pieces are preferably of a highly conducting metal such as copper or brass, which is easily distinguishable from the production workpieces which generally are ferrous in character. The dummy pieces can be used over and over again for the purpose of setting up the machine, and at the completion of production runs. An ancillary object of our invention is to provide an induction heating machine of the foregoing type having automatic means which automatically feeds dummy pieces to the machine right after all production workpieces have been fed thereto, the number of dummy pieces of work being enough to assure that all production pieces have beenprocessed and-discharged from the machine.

A further object of our invention is to provide an induction heating machine of a type described in which pieces of work are fed end to end in a train through an induction heating coil of the machine, each piece being rotated as it passes through the induction heating coil, the machine being provided with means operated by the presence of piecesinsuch train for maintaining it in operation and by the absence of such pieces for cutlting off energization of the induction heating C01 Another object of our invention is to provide an induction heating machine of a type described in which energization of the induction heating coil thereof is cut off whenever the train of work ceases to move through the machine.

Another object of our invention is to provide an induction heating machine of a type described for case hardening selected areas of each production workpiece of a-train of workpieces constantly 3 moving through the machine. In the preferred form of our invention, this accomplished by keying the energy supplied to the induction heating coil of the machine through which the workpieces pass. In accordance with our invention, each workpiece of the train controls the keying of the energy to the induction heating coil, the keying being done in accordance with the hardness pattern desired for axially, or linearly, spaced areas on the workpiece. Specifically, our inven=- tion provides a timer means which is initiated for operation and after such initiation is operable through a cycle in which heating energy is temporarily supplied to a workpiece for obtaining the hardness pattern desired therefor. Preferably the operation of the timer is initiated by a moving workpiece through an initiating switch operated in accordance with the position of a workpiece in the machine. In a form of our invention, the switch is located along the horizontal travel path for the train or" workpieces, and its operation is synchronized with the movement of a workpiece entering the induction heating coil, although its operation .is initiated by another workpiece of the train. In accordance with our invention, the induction heating machine is provided with a plurality of timers corresponding to the different sorts of workpieces to be heat-treated thereby.

Still another object of our invention is to provide an induction heating machine of the type described having a loader portion or means through which a plurality of workpieces are kept aligned side by side and intermittently fed to a moving-means that moves the workpieces end to end continuously through an induction heating and quenching heat-treater unit of the machine. The heat-treater unit comprises an induction heating coil and a quench portion immediately following the induction heating coil in the line of travel of the workpieces. In accordance with an aspect of our invention, the energy to the induction heating coil is keyed, but the quenching water is supplied and flows from the quenching portion constantly. in this way the induction heating coil is efiectively kept cool; and the heat treater unit of which it forms a part can be made small and compact. A utilizable heat-treater unit is described and claimed in the concurrently-filed application of W. L. Corteggiano and J. M. Edwards, Serial No. ll,-- 9 13, now abandoned to which reference may be had for further details thereof.

An important feature of our invention is the provision of a special loader for use with machines of a type described. This loader feeds elongated workpieces to a conveyor moving in a direction corresponding to the length of the workpieces fed thereto. The loader has means for keeping the workpieces aligned side by side and has electrically actuated means for dropping the workpieces one at a time to the conveyor. The machine has parts which receive the workpieces from the conveyor and push them, as a train, in a substantially straight horizontal line there through.

A further object of our invention is to provide a machine of a type described having a detach able work loading magazine. In accordance with our invention, a plurality of such magazines are provided, each being interchangeably attachable for another in the machine; but each being so designed that it will receive onl one particular sort or workpieces. The magazines are quickly changed so that the machine is easily changed from a setup for heat-treating a batch of one sort of workpieces to a setup for heat-treating a batch of another sort of workpieces.

An ancillary object of our invention is to provide each magazine with its own special plug which selects the particular timer which has been or can be adjusted for proper energization of the induction heating coil of the machine in accordance with a particular sort of workpiece which the magazine handles, whereby all guesswork on the part of an operator is eliminated.

Many objects, purposes, features, innovations, methods, combinations, subcombinations, and elements of our invention, in addition to the fore going, will be discernible from the following description of a preferred form thereof, to which we are not limited. The description is to be taken in conjunction with the accompanying drawings in some figures of which details have been omitted in the interests of clarity and brevity.

In the drawings, which are on different scales:

Figure 1 is a plan View of an induction heating machine embodying the principles or" our invention;

Fig. 2 is a front elevation view of a horizontal scanner machine portion of the induction heating machine of Fig. 1;

Fig. 3 is a vertical sectional View substantially on the line III-111 of Fig. 2;

Fig. 4 is a schematic electrical diagram of the electrical arrangement and connections embodying principles of our invention suitable for the machine shown in Fig. 1, mechanical connections between parts being indicated by broken lines therebetween;

Fig. 5 is a side view of the loader portion of the machine of Fig. 1;

Fig. 6 is a front view of the loader portion of Fig. 5;

Fig. '7 is a sectional view substantially on the line VII-VII of Fig. 6;

Figs. 8 and 9 are sectional views substantially on the lines VIIIVIII and IX-IX of Figs. 7 and 8, respectively;

Figs. 10 and 11 are outside views of two different types of workpieces, in the form of shifterrails, that can be heat treated in the machine of Fig.1;

Figs. 12 and 13 are respectively a plan view and a side view of a magazine for the loader portion shown in Fig. 5;

Fig. 14 is a front view of the magazine looking at the right-hand end of Fig. 13;

Fig. 15 is a plan view of a member of the loader of Fig. 5, that is adapted to detachably receive the magazine of Figs. 12-l4, the magazine being omitted;

Fig. 16 is a sectional view substantially on the line XVI-XVI of Fig. 15 with the magazine add" ed; and

Fig. 1'7 is a sectional View substantially on the line XVIL-XVII of Fig. 16.

Referring more particularly to Figs. 1 through 4, an induction heating machine in accordance with our invention comprises a loader portion indicated in its entirety by the reference numeral I. The loader comprises a conveyor 2 on which it periodically places a workpiece W. The conveyor 2 moves the workpieces thereon axially, or in the direction of their lengths, to a work-carrying means which guides and moves the workpieces end to end past an induction heating and quenching heat-treater means. The latter are part of a horizontal scanner machine which forms the subject matter of the concurrently-flled application of W. L. Corteggiano and T. P. Kinn, Serial No. 104,942,. to which reference may be had for additional details. 7

The horizontal scanner machine is. indicated in its entirety by the reference numeral 3 and is supplied with high-frequency energy by ahighi frequency generator 4 that has energizing conductors passing through a, protective casing 5 to .a current transformer B. The current transformer 6 has a secondary provided with low inductance output conductors T.

The scanner machine 3 comprises an understructure table [4 that: may carry the current transformer 6', av bedplate 20 firmly'horizontally secured to the top of the table I4 and carried on the bedplate 2.0 successively in the pathof travel of the workpieces; a feeder 22, a headstock, 24, an induction heating and quenching heat-treater unit 26, and a; tailstock. 28.

The feeder 22 comprises pressure-exerting and work-pushing means 30 and 32.spa.ced along said travel path. The feed-out end of the. headstock 24 comprises a set of work-supporting. and work-rotating triangularly arranged rollers. The heat-treater' means 26 comprisesa head 35 having an induction heating coil portion36 and a quench portion 38. The feed-in end of the tailstock 28 comprises aset 40 of rollers.v similar to those of the headstock.

A feed-in work-supporting: guide, 42 receives the workpieces from theconveyor 2 of'the loader], the work-pushing force of the conveyor be.- ing small but-sufficientzto'slideworkpieces entering the feed-in guide42 to the. pusher means 30 of the feeder unit 22. The guide 42 comprises an elongated bar having a. cross-section: like the bar 44 shown in Fig. 3.. The. bar 44 has a workcontacting V-trough 46 in its upper face in which the workpieces move. Portionsofthe bar 44 can be provided with removable; covers; 41. The pusher means 30 and 32* comprise powerdriven rollers 48 and 50 which slide the train of workpieces along the guide42l and forcethem at a set speed through the restof their horizontal travel path. The guide terminates near the roller set 34 which imparts-rotation to a workpiece thereat so that. the workpiece rotates as it passes first through the induction. heating coil 36 and then through the quench portion 38 of the heat-treater' 26. The quench" portion 38 is supplied with quench liquid, water, through a hose 52, the quench liquid" discharging onto the workpiece through internal holes: in the quench portion in a manner known to the art. Preferably, this water is supplied constantly during operation of the machine.

The induction heating coil 36' of the induction heating and quenching:unit heat treater 26 is connected to the high-current energizing conductors I of the transformer 6- which is: connected to the high-frequency 4'. This generator is preferably a tube oscillator and its energizationof the transformer 6 iscontrolled by: keying its grid circuit. In other words; for selective hardening ofportions-of each'workpiece, the genera-tor power is periodically cutoff and restored;

Asa workpiecepasses through the heat-treater unit 26, it is engaged by the roller set 40 of the tailstock 28 and then passes to a feed-out guide 54 which is similar in construction to the feed-in guide 42, and also comprises an elongated V-troughed bar 44-. Near the end of the travel of the workpieces in the feed-out guide 54, they pass a wheel 56 which rests-lightly on the moving train of workpieces and is: rotated thereby: so

long as. the train is moving, the wheel rotating at a speed proportional to the speed of linear progression of the train, and correspondingly operating an electrical element 51. As each workpiece leaves the feed-out guide 54, it operates an electrical device in the form of an initiating switch 58 having a, pivoted operating arm 60 which is lightly engaged by the leaving Workpiece of the train.

The scanner machine 3 further comprises a variable-speed drive for driving. the lower rollers of the work-rotating roller sets 34 and 40, this variable speed drive comprising a motor 62 and gearing 64. The scanner machine further com.- prises a variable speed drive for rotating pusher rollers 48 and 50' of the pusher means 30 and 32, respectively, of the feeder 22. The latter drive comprisesa motor 66 and gearing 68. If desired, this gearing can also drive theconveyor 2 of they loader I through a variable drive. connection B9.

The loader portion I is shown in greater detail in Figs. 5 through 17; The purpose of the loader portion is to arrange. the workpieces. so that they are properly supplied to. the horizontal scanner machine 3 for heat-treatment. In accordance with our invention, this, loader portion has the added duty of automaticallysubstituting dummy pieces for passagethrough the. scanner machine 3 when theloader: runs out of'prod'uction workpieces to be heat-treated, morespecifically to be case hardened. Also, in accordance with our invention, theloader is designed with a detachable portion or magazine so: that azplurality of interchangeable magazines can be used with the singleloader, eachmagazine being designed to receive a single. sort. of workpieces which is diiferent from that receive'dby'another magazine.

In. accordance with. the preferred form ofv our invention, the loader portiorrl comprises a supporting framework T8 which. includes apair: of spaced upright posts 12 and 14', and a reinforcing cross bar 15 across their. uppenends.v The framework carries a chute: member 16, azworkpiece magazine 18 detachably secured to the chute member'lfi, the conveyor2, anelectrlcally operable work-releasing means comprising re.- lease rods-82 andM operated by'releasesolenoi'ds 8B and 88, respectively, and an. automatically operable selector means indicatedin its: entirety by the reference numeral 90.

The solenoids 85 and 88 are carried'by the framework W and have armatures attached to the associated release rods 82 or 84 through spring biasing means 92 and 94 which tends to place each of the barrier rods 82 and 84 in the positions shown inFig. 16 when the associated solenoid is deenergized. The release rods 82 and 64 control the release ofwork on the con:- veyor 2'; and the selector means allows only production workpieces inthe magazine. 18' to reach therods' 82 and-84 until'the last such workpiece leaves the magazine. In such case the selector means QDoperates to allow d'ummy pieces to reach the rods 82 and: 84,.

Workpieces released by the release means comprising the bars 82 and 84' drop onto the conveyorv 2. for conveyance to. thefeed-in guide 42. To this end the. conveyor 2 comprises an endless belt, the upper-run of which is preferablvhorizontal but can be slanted downwardly somewhat if desired. The conveyor beltis, carried on supporting drums. mounted. on pillow blocks. 95'. car'- ried by the framework 10. The conveyor belt moves in the direction of the arrows shown in Figs. 2, 4, 6, and 7, being constantly driven by the gearing 60 driven by the electric motor 66 01' the scanner machine 3. Obviously, however, this belt can be separately driven if desired.

Immediately above the conveyor belt, the framework I of the loader I carries a pair of elongated guide bars 98 and I00 parallel to the conveyor belt. As shown more particularly in Figs. 5, 8 and 9, the guide bar 98 is partly an angular member having a vertically disposed leg H32 parallel to a vertically disposed leg I04 of the guide bar I00. The leg I02 of the guide bar 598 terminates just short of the delivery end of the selector means 90 from which the rod-like pieces of work roll one at a time onto the conveyor belt to the position shown by the lower dashed lines in Fig. 9. The upper part of bar 8 comprises a longitudinally extending portion I; the space between this portion and the belt 2 providing a gateway through which a workpiece passes. A released workpiece rolls through the gateway and onto the conveyor belt 2, being stopped by the leg I04 of the guide bar I00. The conveyor 2 moves this workpiece between the guiding legs I02 and I04 of the guide bars 95 and I05, the entrance or feed-in end of the bar 08 being slightly bent out as indicated at Iii-ii in Fig. 9 so as to avoid jamming. The con veyor carries the workpieces between these legs it? and I04 and discharges them into the feedin end of the feed-in guide 42, constantly pushing leading workpieces into the pusher means 42 and 44 of the feeder 22.

The pieces of work which are delivered to the conveyor 2 come from the chute member I6 of the magazine I8. Referring more particularly to Figs. 5 and 15-17, the chute member 16 has a bottom plate I06 that extends to the gateway provided by the guide rail 98. This plate I06 is inclined to the horizontal except for a short delivery end portion I01, as shown more particularly in Figs. 5 and 16. The release means comprising the release bars 82 and 84 is arranged and operated so that the pieces of work are fed to the conveyor 2 one at a time. To this end the delivery end portion I0? of the plate I06 has a small rectangular hole H0. The upper release bar 82 is above the hole and has a dividing nose H2 slightly above the hole. The lower release bar $4 is below the hole except for a stop nose H4. With the solenoids 00 and 83 of the has and t4 deenergized, the noses H2 and H4 are in the path of movement of pieces of work from the plate I06 to the conveyor 2, the noses spanning a single piece of work. When the lower solenoid 88 is energized, it pulls its associated nose 5 I4 of the release bar 84 below the end portion E0? of theplate I06, and allows the workpiece between the noses to roll onto the conveyor. iii the solenoid 80 is then deenergized, the spring bias forces the nose H4 back into the travel path for the pieces of work. By subsequent momentary energization of the upper solenoid at, the nose H2 is raised allowing a piece of wort: to roll against the nose H4. Upon deenergization of the upper solenoid 86, the nose I it lowers and this piece is caught between the noses H2 and H4. Subsequent energization of the solenoid B8 releases this ready piece of work, but another cannot roll into its place because of the barrier interposed by the nose H2 of the release bar 82.

' Either dummy pieces or workpieces are fed by the selector means to the release means described. The dummy pieces are fed to the selector means through a structure which is shown more particularly in Figs. 16 and 17. The dummy pieces ride on the upper part of the plate I06 of the member I6. The plate I06 has a pair of parallel angles I28 and I30 welded or otherwise secured thereto and terminating at an intermediate portion of the plate I06 in the region of the selector means 90. These angles I28 and I30 provide a chute or way I34 for the dummy nieces d, each of which may simply be a smooth cylinder of brass that can roll down in the way I34 to the selector means 90 through the action of gravity.

The selector means 90 comprises a short bridge-like structure carried on the bottom plate I06. This structure comprises a pair of upright side walls I38 and I40 that have sloped top edges on which a top I42 for the structure rests. The top I42 slopes more than the plate I06. The sides I36 and I 40 and the bottom plate I06 of the loader detachably receive a loader magazine it in manner that will later become apparent.

Referring more particularly to Figs. 12 through is and 17, the magazine I8 comprises a lower inverted U-shaped member I43 having upstanding sides I44 and I45 and a top or crossbar I46. The lower end of the member I43 is provided with securing ears I43 and I49 extending outwardly from the ends of the sides I44 and I45. The upper portion of the member I43 is provided with additional securing ears or flanges I50 and IiiI extending outwardly from bottom portions of the sides Id4 and I45.

The magazine IE further comprises an upper channel member I53 having downwardly extending legs I54 and I55 and a top crossbar I56. The legs I54 and I55 of the member I53 are secured to the outsides of the legs I44 and I45 of the member I43 with the crossbars I46 and I56 vertically spaced to provide a chute or way I50 for production workpieces to be heat-treated. As shown in Figs. 5 and 13, the member I53 is shorter than the member I43. Consequently the member I43 protrudes upwardly beyond the member I53 and provides a protruding upper platform on which an operator can place production workpieces that roll down the way I59. Each magasine I0 is designed so that the width of its way I58, that is, the distance between the sides I54 and I55, is only slightly greater than the length of the particular workpieces to be associated therewith.

Figs. 10 and 11 illustrate sorts of workpieces for which magazines 18 can be provided. In Fig. 10, the workpiece comprises a shifter rail W" having three circumferential or annular notches or grooves I60, I6I and I62, the groove I60 being at the left-hand end of the shifter rail and the grooves NH and IE2 at the right-hand end. The distance from the groove It?! to the lefthand end of the rail is different from the distance of either groove I6I and I62 to the rigl1t-hand end of the rail. Fig. 11 shows another form of shiften-rail W provided with non-symmetrically arranged circumferential or annular grooves I53, I64, I65 and I 66, the distance from the groove I63 to the left-hand end of this rail being different from the distance from any of the other grooves to the right-hand end. It is to be noted that not only is the form or shape of the shifter rails of Figs. 10 and 11 different but that their lengths are also different, and our induction heating machine has adjustments which permit 9.; their diameters to be different also. Consequently, itshouldbe understood that the shifter rails W and W are merely representative. of workpieces treatable in our machine, so that the machinev is not limited to the treatment of the exact workpieces shown.

The workpieces treated. usually have grooves and, in accordance with. our invention, advantage is taken of this fact toprovide a magazine which will receive only the specially placed grooves of one particular sort of workpieces. To this end, the bottom floor of the way I58, which comprises the cross bar I 46 of the member I43, has secured thereto a. pair of positioning. runner rails I68 and, I which are parallel to the sides I54 and, I55. are spaced to correspond to the spacing between grooves of a particular sort of workpieces. The distance between each positioning runner rail and the nearest side corresponds to the distance between a groove of ashifter-railandthe nearest end of the shifter-rail, the distances being. so chosen that they are not duplicated by any other shifter-rail to be heat-treated. in the machine. Preferably also, the height between. the crossbars I46 and I56 of the way I58 corresponds generally to the height of the workpieces-riding: on the-positioning runner rails so as tofurther confine the workpieces; the distance between the top bar I 56 andthe bottom I46 being only enough to provide a space that will receive a workpiece whose grooves fit the runners I88 and. I .10. Consequently, a magazine 18 can be provided which will receive only shifter-rails for which it has been. designed.

In accordance with our invention, a plurality of magazines I8. are provided each having a chute-way designed for the particular. workpiece to be loaded through the particular magazine. All magazines, however, have securing ears. or flanges. provided. with holes located. in the same place for. all magazines so that the magazines can be interchangeably detached. to the lower chute member. 16 and selector. means 80 of the loader I. To this end, as shown more particue larly in- Fig. 17, the upright lugs I48. and M8 of a magazine abut against the ends of sides I38.

and I40, and have suitable slots I13 for receiving fastening bolts or other suitable quick-release detachable fasteners that fastenv to the ends of the sides I33. and. I40. In this position. the outwardly directedflanges I50 and. I5I. of. a: magazine rest on outwardly extended. portions of the bottom plate I06 of. the lower member I8, and,

these abutting portions are similarly provided with properly. spaced holes for receiving quicklyreleasable fastening. means.

Anouter side of each magazine I8 also has circuit-selecting or -closing plug I14. attached thereto by means of. an elongated cable I16, the plug for each magazine fitting a receptacle I1"! (Figs. 1 and'4) carried. by theframework 7.0.01

table I4. The receptacle IT!: is connected to a.

descriptions of operations applying toa. first of C The runners I58 and Iii-5i- 10 them can readilybe understoodv as applicable in generaltoany other.

As is moreapparent from Fig. 16, witha magazine attached, the loader portion. I comprises. two.

downwardly sloping. parallel. chute-ways I34. and I58, the way I58 being over the way I34. Both extend to the selector 90 whichallows only work.- pieces in the upper way [58- to feed to the conveyor 2. until it is empty after which it automatically moves to allow dummy. pieces d tofeed from the lower way I34 to the conveyor.

Workpieces leaving. the way I58. of themagazine I8. roll down on the inclined wall or floor. I42 of theselector. means 90. This. incline has a lower tilta-ble. barrier member I 80. The barrier fioormember I is secured to a shaft I82 through. a pair of spaced support bars I84 and I85. that. lie.

in the lower way I34 when the barrier floor member I80 is inthe solid line position shown in Fig. 16. The. shaft I 82 is rotatablyjournalled inthe" side walls I38 and I40, and-amend extends outwardly to receive a counterweight I81 ar-- ranged to provide a turning moment acting in can be provided with top members I90 to prevent a workpiece from riding on another. To accommodate different lengths of workpieces,

the bars I88 and I85 are adjustably secured tov the floor member I42 and bottom plate "16- of the chute member 16. Thus,- several series of holes I8I are provided, in any of which thebars I88-and I 89 can beremovably secured.

The tiltable floor member I80 for the loader is provided so that dummy pieces of; work will automatically be fedfrom. theway I34 to the conveyor belt 2 whenever: the last ofthe workpieces in the magazine 18: passes therefrom. To this end, the way I34 is provided-with a predetermined number of dummy pieces 01- which have lengths that add-up: to at least. the distance from the feed-in end of the induction heating coil 34 to the initiating switch 58. Innormal operation, the first of these dummy pieces 11- bears against abutment edges I92 of the support bars I84 and I86 for the tiltable member I80, the barsbeing spaced less than the length of a dummy pieced. These edges I92 of the bars I 84 and I'BGareimmediately under the shaft I82. There is some force exerted. by the dummy workpieces (1 against the abutment edges I82. that tends to lift the tiltablefloor member I80. between. the

counterweight IBI is no; longer opposed,. and the shaft I82 will turn so: as to raise the tiltable" floor member I80, the bars I84 and Ififi moving through slots I93 in' theupper floor member I42.

The floor member I80 moves to' thebrokerr line position shown in Fig. 16, allowing dummy pieces to roll down the bottom plate l2t so that they reach the release mechanism comprisin release bars 82 and 84.

It is to be noted that a protective switch Hi l has an upwardly biased operating bar 1% p jecting upwardly through a small hole in the bottom plate [06. This hole is located so as to be covered by the end of the tiltable floor member 18b when the end rests on the plate )5. Normally, the floor member I81] depresses the operating bar I98 to keep the switch E94 operated. When the floor member I86 rises, the switch condition changes, but each dummy piece d rolling or resting over the aforesaid hole also depresses the operating bar 195 so as to operate the switch 194.

Brief operation of the scanner machine In the operation of the parts thus far described, a magazine 78 is attached to the chute member 16 and its plug H inserted in a suit able receptacle therefor. Assume that an operator keeps the magazine filled with the P ticular shifter-rails for which the magazine 1s designed. The shifter rails roll down the macazine, keeping the tiltable floor member Hit in depressed position and the switch Hid operated. The shifter rails are released to the conveyor belt 2 one at a time by sequentially spaced mo mentary energization of first the solenoid 88 and then the solenoid 86. The conveyor moves the released rail between the guides 96 and Hit and into the feed-in guide 42 of the scanner ma chine 3. The conveyor belt runs just a little faster than the train of rails in the scanner ma chine so that there is never any gap between rails of the train in the scanner machine As the entering shifter-rail moves along the feed-in guide 42, it passes between the rollers 48 and 53 of the pusher means 32 and 3d of the feeder 22 which pushes it through the scanner machine 3. After leaving the pusher rollers 48 and 55 each rail moves into the headstock 24, into the set 34 of work-rotating rollers of this headstock, and from there into the induction heating coil 36 of the head 35 of the induction heating and quenching unit 26. As each rail moves through this induction heating coil, the high-frequency generator 4 is keyed so as to apply high-frequency heating energy to the coil 36 for inductively heating the rail at certain portions only of its length, preferabl those at the grooves of the rail. To this end, the rails must key the RF generator. In accordance with our invention, this keying is done b a timer mechanism to be later described which can operate through a cycle initiated by each rail passing a predetermined point in its line of travel. Preferably, the rail is that leaving the feed-out guide 54. Consequently, it is dc" sirable to secure the initiating switch 58 on the bedplate 20 in a longitudinally adjustable man" her, so that the time of its operation by a rail for initiating an operation cycle of the timer, is time-related to the position and speed of a rail entering the induction heating coil 36. The speed factor can be eliminated by having the train of rails pass through the scanner machine at a predetermined speed. Preferably also, the wheel 56 is adjustably placed along the ieedout guide 54 so that it prevents a rail from tipping from the guide before the end of the rail actuates the initiating switch 58. In other words, a leaving rail tilts off the end of the iced-out initiating switch 5%, after which it also tilts and falls from the feed-out guide.

In Fig. 4, elements or the induction heating machine hereinbefore described are shown schematically, mechanical interconnections between elements being shown by broken dashed lines and some items being enclosed in broken dotdash lines to identify them. Thus, the loader I has aligned side-by-side workpieces W on the inclined plate I46 of the magazine Hi and on the inclined floor member of the selector 9E), including the floor member {80. So long as workpieces are on the delivery end or the inclined floor member I80, the operating member I96 of the switch H94 keeps the switch closed. When solenoids 86 and 88 are suitably operated, single workpieces are released by the release bars 82 and B4, and each workpiece rolls onto the conveyor 2. The conveyor 2 feeds the workpieces to the horizontal scanner machine s where they successively pass the work-pusher means 33 and S2 (driven by motor 56 through gearing 68) the work-rotating roller-set 34 of the headstock (driven by motor 62 through gearing 64) the induction head 35 (comprising the induction heating coil 36 connected by conductors 1 to the transformer B, and the quench portion 38 fed by water through hose 52), and the work-rotating roller set M! of the headstock (driven by the motor 62 through gearing E54).

In moving through the machine, the train of workpieces rotates the wheel 56 at a speed proportional to that of the progression of the workpiece-train; the wheel 56 being mechanically interconnected to a double pole reversing switch 51 and operating it in timed sequence proportional to the rotation of the wheel 56.

As a workpiece moves it operates the switchoperating member 60 at a predetermined point in the line of travel of the workpiece; more specifically near the end of its travel, just before it falls from the machine. Such operation of the operating member 69 momentarily closes the switch 58 to which it is mechanically interconnected.

Unless suitable controls are provided for a machine of the type described, the energy supplied to the induction heating coil may be sufficient to melt a workpiece if the train of rails does not travel at or faster than the desired speed; and, consequently, considerable damage might be done to the machine. In accordance with our invention, we provide automatic means which not only keys the energy supplied to the induction heating coil in accordance with the areas of the surface of each workpiece desired to be case hardened but also prevents energy from being supplied to the generator should the train of rails move slower than the desired speed as it might do should the train jam. Controls are also provided to cut off energy to the induction heating coil after the last of the available production workpieces has left the machine so that no untreated production workpieces will fall into a batch of heat-treated workpieces in a container or bin I91. Furthermore, it is desirable not to apply energy to the induction heating coil until the machine is in proper operating condition as determined from dummy pieces of work moving through the machine at the proper rate. For accomplishing the foregoing and other 0bjccts, we provide the machine with a preferred electrical circuit control schematically indicated ace-430m;

13 in Figure. 4; this; circuit. beingintegrated with. the various controlling switches and induction heatingcoil. of the machine.

H igh-freq uency generator control relays Thea tube-oscillator: 4 has: three status-conditions; first an inoperative: condition inwhichits: parts-are. not; in general, energized; second. a: stand-by conditionin which its parts. are..in..genieral, partially energized but the generator: is not delivering high frequency energy to. the. trans;- former. 5, and third, a'poweredelivery condition: in.which thegenerator. delivers high-frequency. power to: the transformer 6 andhence tothein duction. heating. coil 36; The controls. inside; thegeneratorfor this purpose are not'pa'rt of our: invention and any conventional. or: suitable cir*-- cuitscan. be provided therefor as is known to the art. In Fig. l, a stand-by relay 2%. shown as inside.-the' generator 4; andicontrolsa' branch-circuit 202 which, in turn. controls;pow'-- e-r-circuits to parts. of the generator. Therelay 200 has an operating coil: 2% which is connected. in. series. with controlling. contacts and switches to, be described, so that these contacts andswitches. control the energization and deenergization .ofthe branch-circuit 20.2 for. controlling" the. generator. For example, the branch-cir cult 20.2.can control.theapplication. of. the D. C. plate. voltage.- When. thebranch-circuit is deenergized, .no plate voltage is applied to thetubes' of'the generator, and the generator is in its first condition. When the. branchecircuit is energized, the. plate power is applied and the generator is. in. its second, or stand-by, condition; For. placing. the generator in.- itsthirrl or powerdelivery condition, a keyingrelay 2041s provided" havingnormally-open. contacts 20d and an op= crating coil. 208. Whenever; the coil: 2138 is en= ergi'zed, contacts 20.6.- close and may; complete grid. circuits. of the generator.

Cycle-timer selection The keying of the relay 204 is. done by the particular cycle-timers, for. example, F1811 or H811 whichareselected by the particular. magazine 18 used. with the. loader l of. the machine; The magazine 18', through. its plug I14; deter-- mines? which timer. willbe operative. As illustrated at the left of Fig.

[1.41). represent the. plugsof. two. different work loader" magazines 18. Each. plug. can. be individ'ually fitted to the receptacle I11, but eachiplug has a-diiierent connection 219a and "Zlilb, re.- spectively, for differently connecting the con ductors leading to the receptacleso asto select its proper'cycle-timer for the particular sort of workpiece in the. magazine. to whichthe plug; is attached by the chain I75. Inoperation, a 07, ole-timer also operates the. release solenoids 86; and" 88" for the loader;

Cycle-timers Each cycle-timer is of" a conventional. type which, upon receiving a. starting impulse,. op-- eratesthrough a single predetermined. timed oycle' andthen stops until it receives another start-- ing impulse. During. its. cycle the timer sequentially closes a plurality of circuits for predetermined adjustable periods. To this end,. eacliof the timers. [18a and I181) comprises; re.- spectively, a constant speed motorZJZa, and 2121),. the. speed. at. which .it. runs being. adjustedinanv suitable. manner. Each of the motors.- 2|.2a. andi 2.1.211- drives, respectively, cam-shaftss'llfiar and- 4, two plugs HM and" fitted. in the receptacle. I11.

21 filrhavingga; plurality; of;sw-itchpoperatingqcams:

213a; 252011;. 222m. 221411;. and- 21l8b; 2211b; 2221);:

which provide holdingcircuits: 226w and. 2261);.

respectively; for" maintaining. the? associated mo:-- tor: energized. for itsstimer-cycle;

The cams" 220a: and: 22Gb can operate switches: 228a; and 2281), respectively. Each cam. cant be adjusted for closing its; switchoncei or. a. plu+ rality of times within the cycle of operation: of. the:- associated" timer; Theswitchesz 228a; and Nab-independently control. a circuit? 230 to the operating coil. 208-. of "the: keying: relay 20.4.

Each. ofthecams 222w and'222b' can. operateits" associated switch briefly once during; the timer.- cycle; the switch: controlling a. circuit" 232 to" re-- lease sol'enoidiBB; Each of the cams-124a and 2246 can operate its associated switch briefly onceduring. its:timer:-cycle;- the switch controlling acircuit"234 to' the release. solenoid 86. The" cam-adjustments off a timer" are such; that the solenoid 8B is operated: and releasedbefore-the solenoid 86 is operated. The time required. for each timer to complete-a cycle is just less than the time requiredfor; aishifter rail to passafi'xed point initstravel path in thes-canner machine:

Major preparations-for operation (electrical) Assume=that the: equipment is shut down and that it is: desired to case. harden a: plurality of. selected areas; only on a; shifter rail such: as shown in Figs; 10 or. 11 ,.the-- areas being the grooved. portions. of; the: shifter rails. First the.

proper magazine. lBLisattacliedjnthe loaderportion, and its plugg. assumed. to be: plug. lHa, is. The cams. of the timer; lFiEaare; suitably adjusted in accordance with the distance: or the: operating:- member 69 off the initiatingiswitclfriflz from the. heat'rtreater; head; the: desired speed. of travel. oi thev train of." shifter: rails; and: thee spacing of; the grooves on" a: shiiter. rail. imparted to: a; shifters-rail depends; on. the speed of: the train; other. things. being equal.

Dummy piecesof brassior similar. metal and ofv a length equal to the-shifter rails are: first. placed in:thezloader.;- and: the: main power supply switch. 24hr the lower right: center-of Fig. l is; closed.

- Power from mains-2.42 and 244 is; applied to an.

; motor-start relay- 258' is energized. The relay 2-58 closes its contacts 260; connecting power from-mainsZA-Z' and 244 to the motors 62' and Stand to aprotective relayZBI As aresult con-. veyorZ: and the rollers of pusher means 38 and I 32 operate to push work through the machine and the roller sets 34 and 4B operate to rotate each pieoe of work passing through the heattreaterhead' 35'; At this stage of the starting operations; thepieces of" work aredummies and are fed by -liand to the conveyor 2. Operation- In-cidenta-lly,. the case; depthv A hand operated operation switch.

of protective relay 26! causes it to close its contacts 262 but no circuit is thereby completediat this point.

With power on conductors 244' and 256 a charging circuit 263, shown in the lower righthand corner of Figure 4, is completed, this circuit 263 comprising a half-wave rectifier 264 and. a large capacitor 266. Connected across the capacitor 266 is a circuit comprising the operating coil 268 of a sensitive relay 210 and an adjust able resistor 2'H connected to the blades 212 of the double pole reversing switch 61. The train of dummies moving through the machine rotates the speed-responsive wheel 56 which in turn operates the reversing switch 51'. Operation of the blades 212 of the switch alternately reverses the polarity of capacitor 214 which is much smaller than the capacitor 266. When the wheel 56 comes up to speed, the sensitive relay 210 receives a series of direct current pulses the average of which is adequate to operate the sensitive relay 210 and it closes its contacts 216 but noth ing happens pending subsequent operation of additional contacts.

As the train of dummies passes through the machine, each leading piece operates the operat ing member 60 for the initiating switch 58. With the plug 114a in the receptacle Ill and with power across auxiliary mains 24-4 and 256, a momentary closure of the switch 56 closes a cir cult that traces as follows: the main 244', the switch 58, the conductor 28!) of the receptacle ill, the cross conductor 2l0a of the plug Ilsa, the conductor 282 of the receptacle ill, the motor 2 [2a of the timer (18a, to the main 256. The motor 2I2a starts to rotate and its cam Zita closes the associated switch to close the holding circuit 226a for the motor, this circuit remain ing closed until the timer-cycle is completed so that subsequent opening of the initiating switch 36 when the aforesaid leading piece of work falls from the machine will not stop the timer H811. As the timer goes through its cycle its cams 222a and 2240, sequentially connect circuits 232 and 234 across the mains 244 and 256 so as to sequentially operate the release solenoids 80 and 86 to release a piece of work to the conveyor 2 to replace the piece leaving the train at the other end of the train. Also the cam 226a keys the keying relay 204, but this has no effect on the generator 4 at this time.

The preparatory set-up includes a water supply that feeds cooling water to the generator 4 and the induction heating coil 36 and feeds quench water to the quench portion 38. This water supply may contain a pressure responsive protective switch-contact 284 in a circuit to the operating coil 203 of the stand-by relay 200, the contacts 224 remaining closed only so long as the water supply is proper.

Heat-treating operations Assuming that the preparatory adjustments and operation are all satisfactory, the apparatus is now ready to heat-treat production workpieces. The operation control switch 248 is moved from Scanner Only position to full operation position.

The contacts 252 are opened, momentarily stopping al1 moving parts by temporarily deenergizing the main 256. The contacts 250 of the switch 248 are closed so as to prepare the circuit 202 through the operating coil 203 of the stand-by relay 200; this circuit leading through the coil 203, the contacts 250, the water-protection contacts 284, the contacts I94 closed by the presence of work on the inclined plate 106 of the loader I, to a point P.

The start button 300 is now closed, closing its' contacts 302 and 304. Closure of contacts 302 completes a circuit to a signal light 305 and to the operating coil 306 of a relay 306; the circuit passing from main 242', through contacts 302, and the coil 306, to the main 244'. The relay 308, now energized, closes its contacts M0 and 312.

Closure of contacts 312 of the relay 303 completes the rest of aforesaid circuit for coil 203 of relay 200, from the point P, through the contacts 3 12, the normally-closed contacts 330 of the stop button, the held-closed contacts 304 of the start button, to the other side of the branch-circuit 202. As a result, the relay 203 energizes, closing its contacts 313 and 314. The closed contacts 3l4 are connected in parallel across the now open contacts 252, so that closure of the contacts 3| 4 reconnects the supply main 256 to the end 254 of the autotransformer 246.

Closure of contacts 310 of relay 333 completes a circuit from main 244', the contacts 310, the

operating coil 3| 5 of a relay 3|6, and a conductor l 3 connected to the main 256. Operation of relay 316 closes its contacts 320. Closed contacts 320 complete a circuit from main 244, the closed. contacts 320, the operating coil 322 of a control relay 324 to the conductor 318 connected to the rnam 256. The operated relay 324 closes its contacts 326 and 328 which prepare circuits later described.

At its contacts 3l3, the relay 200 closes a holding circuit around the start contacts 304, so that the relay remains energized when the start button is subsequently released, the holding circuit including the contacts 330 of the stop button.

When main conductor 256 is reenergized by closure of contacts 3 l4 of relay 200, the relay 258 is reenergized whereupon the motors 62 and 66 are restarted and the relay 26! is re-energized closing its contacts 262.

Inasmuch as contacts 328 of relay 324 are closed as before described, closure of contacts 262 completes a second branch 336 from the point 13. This branch contains the contacts 262 and e28 in. serles, and is in parallel with the contacts 312 of the relay 308 energized by depression of the start button. Consequently, the circuit for the relay 200 has an alternative path through branch 336, the stop button 330 and contacts 3 [3 should the start button be released and deener glze the operating coil 306 of the relay 308. However, the start button should be held closed for a while to insure the re-starting of the motors 62 and 66 starts the train of work and brings it up to speed for operating the wheel 56 until the ensitive relay 210 operates. This relay closes its contacts 216, completing a holding circuit for the operating coil 322 of the control relay 324 this holding circuit being traced as follows: main 244 contacts 326 and 216, coil 322, conductor M8 and main 256. Consequently, the branch 336 d so long as power is at the motors 62 and 64 for keeping 1153 2 6? energized to maintain its contacts 262 closed. As a result the stand-by relay 200 remains energized W1th the relay 200 energized, the generator is in stand-by condition to supply high frequency gower to the transformer 6 and such power can Pe transferred to the induction heating coil 36 rooductlon workpieces can now be supplied to the ina az ne 78. As each piece of work leaves the ram, 1t actuates the switch 58 that starts the proper timer I16 through its cycle. The timer keys the relayZM tocause-highfrequency power to be supplied to the heatinggcoil for short periods whenever a. section of a workpiece which is to be hardened is passing through the induction heating coil. The timer also releases another workpiece onto the conveyor 2, through operation of release solenoids 88 and.

An example of workpieces heated. in our machine comprises shifter rails of a type shown in Figs. and 11. Shifter rails V inch in diameter were case hardened at selected areas only. Batches comprised rails having a length of 41% inches, 6% inches, and 65-2 inches. The rails of a batch were S. A. E. 1046 steel and were moved through the machine at a speed .7 inch per second or at .76 inch per second. For a speed of .7 inch per second and rails 4 7; inches in length, having three closely spaced grooves, the timer was keyed one time by the keying relay 204 for a keying period lasting 1.05 seconds. The generator supplied high frequency energy at a frequencyof 450,000 cyclesper second.

Some protective features Should either motor 62 or 64 draw excess current, a thermal element 350. at the main switch 240- operates to deenergize the main 244'. The control relay 322 is. deenergized, opening its contacts 328 in the branch circuit 336 for the stands by relay 200. The stand-by relay 200 opens its contacts. 332 and 334, and the generator is placed in its initial inoperative condition.

Should a. rail jam in the machine, the wheel 55 will not rotate at the required speed, and as a result the sensitive relay 2'"! becomes deenergized and opens its contacts 216. The control re1ay'322 i deenergized this time through opening of the contacts 21.6:in itsholding circuit. The generator 4 will not be operative to deliver power to the stalled train of workpieces.

If production workpieces cease being supplied to a. magazine l8of theloader, the dummy pieces are fed to the conveyor 2 until all production workpieces have been heat-treated. When the last of the dummies leaves the loader l, the protective switch I54 stays open, deenergizing the stand-by relay 200 before the last of the dummies has passed through the induction heating coil.

It is to be noted that whenever the stand-by relay 200 becomes deenergized, the main 256 is disconnected from the end 254 of the autotransformer 246, by opening of contacts 3M. As a result the machine shuts down.

The machine can be normally shut down by depressing the stop button and opening its contacts 330 which are in the circuit for the standby relay 200.

While we have described our invention in a preferred embodiment, it is obvious that its principles and teachings are of general application and can be embodied in other embodiments.

We claim as our invention:

1. An induction heating machine of a type described for heat-treating rod-like workpieces comprising in combination, an induction heattreater means having a central work-receiving opening, a loader having a work-container magazine and a dummy-containing portion, workcarrying means for guiding and moving workpieces end to end through said heat-treater means for heat-treatment, means for releasing workpieces one at a time from said magazine to work-carrying means, and automatic selector means operable to supply dummies from said 1'8 dmnmy-containing portion to be released to said. work-carrying means when said magazine becomes empty with energizing, means for said heat-treater means, and a. control for said energizing means in response to the position of said automatic selector means.

2. An induction heating machine of. a type described for heat-treating rod-like workpieces comprising in combination, an induction heattreater means having a central work-receiving v opening, a loader having a work-container magazine and. a dummy-containing portion, workcarrying' means for guiding and movingv work.- pieces end to end through said heat-treater means for heat-treatment, means for releasing workpieces one at a time from said magazine to said work-carrying means, and, automatic selector means operable to supply dummies from said.

dummy-containing portion to be released to said work-carrying means vwhen said magazine becomes empty, said loader: comprising a wallbetween said magazine and said dummy-containing portion, said wall comprising a biased portion biased towards a first position to permit dummies to be released, said biased portion being held in a second position by workpieces in said magazine to prevent release of dummies, with energiz ing means for said heat-treater means, and a control for said energizing means, comprising a switch operable in response to the position of said biased wall-portion relative to the position of said switch.

3. An induction heating machine of a type described for heat-treating rod-like workpieces comprising in combination, path-providing means for successively moving workpieces alon a path with the workpieces moving linearly in the direc-= tion of their lengths; loader means through which workpieces are fed to said path-providing means; said path-providing means comprising successively in the direction of movement of work= pieces: a first work-supporting and rotating means, a heat-treater means. comprising an in duction heating coil, and a second Work-supporting means; high-frequency generator means having connections for energizing said induction heating coil; said loader means having a switch means associated therewith, said switch means being arranged to be operable in accordance with the workpiece load in said loader means, and correspondingly controlling the application of energy from said generator means to said induction heating coil; and switching means operable by movement of workpieces along said path for also controlling the application of energy from said generator to said induction heating coil so the amount of energy applied to each portion of each of the workpieces may be thereby controlled.

4. An invention in accordance with claim 3 but further characterized by the last said switch= ing means comprising a wheel arranged to rotatably engage workpieces moving along said path.

5. An induction heating machine of a type described for heat-treating rod-like workpieces comprising in combination, an induction heattreater means comprising an induction heating coil and quench ring having a central workreceiving opening, a loader having a work-container magazine, work-release means comprising a pair of spaced stops in the path of workpieces in said loader, electrical means including stopmoving devices for moving said stops out of said path to release a single workpiece, means for receiving released workpieces and pushing a train of workpieces end to end through a path including said opening, high-frequency energizing means adapted to energize said induction heating coil, and electrical means comprising a timer means initiatable to operate through a cycle for causing said energizing means to energize said induction heating coil periodically during said cycle, and for selectively operating said stop-- moving devices, and a switch means, a weight operated member in said loader, said member being weighted by workpieces in said loader, said switch means being operated by said member for controlling the energization of said induction heating coil by said energizing means.

6. Apparatus of a type described comprising in combination, a machine for heat-treating batches of shifter rails, the rails of a batch being sub" stantially the same size and shape but different from those of a different batch, each rail having a plurality of axially spaced grooves to be hardened inductively, an induction heating coil, a plurality of timer means each for controlling the periods or energization of said induction heating coil for selective heating of each rail, means comprising a detachable magazine for feeding rails end toward end through said induction coil, said magazine comprising means arranged thereon so as to receive only one sort of rails, and control means associated with said magazine cooperating only with the timer adapted to cause energization of said induction heating coil in accordance with the sort of rail in said magazine.

7. In combination, heat-treating apparatus for treating a plurality of different types of workpieces comprising a detachable magazine which is adapted to receive only one type or workpiece to be heat treated and control means attached to said heattreating apparatus for controlling the operation thereof for heat treating the workpieces in accordance with the type of workpieces in the magazine, said magazine bein adapted to feed said workpieces to be treated into said heat-treating apparatus.

8. A magazine for containing workpieces to be fed into a heat-treatment apparatus for treating said workpieces, said heat-treatment apparatus including control means for controlling the operation of said heat-treatment apparatus, said magazine being adapted to receive only one type of workpiece to be treated, with said magazine com-' prising contact means adapted to contact said control means so as to cause said control means to operate in a predetermined manner dependent upon the type of workpieces in the magazine.

WILLIAM L. CORTEGGIANO. MILTON P. VORE. JOHN M, EDWARDS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,615,220 Gaine Jan. 25, 1927 1,682,999 Tenney Sept. 4, 1928 1,697,811 Dailey Jan. 1, 1929 1,705,082 Brigham W Mar. 12, 1929 1,749,262 Roark Mar. 4, 1930 1,806,879 Lindgren May 26, 1931 1,649,238 Lindgren Mar. 15, 1932 2,037,931 Schmidt Apr. 21, 1936 2,202,759 Denneen et a1 May 28, 1940 2,218,444 Vineyard -1 Oct. 15, 1940 2,237,659 Edwards Apr. 6, 1941 2,249,529 Knights July 15, 1941 2,325,638 Strickland Aug. 3, 1943 2,357,888 Gookin Sept. 12, 1944 2,363,724 Ford -1 Nov. 28, 1944 2,393,363 Gold et a1. Jan. 22, 1946 2,400,472 Strickland May 14, 1946 2,410,492 Garrow Nov. 5, 1946 2,417,678 Cox Mar. 18, 1947 2,430,005 Denneen et a1 Nov. 4, 1947 2,465,306 Durand Mar. 22, 1949 2,470,707 Leston et al May 17, 1949 2,572,073 Strickland et al. Oct. 23, 1951 2,578,760 Strickland Dec. 18, 1951 

